Apple is moving toward the March 31 deadline for complying with the terms of its settlement with the FTC over in-app purchases, and the company is alleged to have run into technical difficulties when implementing changes to the iOS App Store.

Apple underestimated the time required to bring the App Store into compliance, sources toldZDNet. The publication speculates that the issue could be due in part to the need to make additional changes to iTunes on the desktop, with the app's 13-year-old codebase presenting a challenge.

As part of the settlement, reached with the FTC in January, Apple agreed to modify the in-app purchase process to ensure each purchase was expressly authorized by the consumer. That likely means abolishing the current 15-minute window in which users do not need to re-enter their password after making an initial purchase, a period in which children or other unwitting users have accidentally racked up huge bills.

The changes may also be delaying the release of iOS 7.1, ZDNet surmises. Apple is thought to want to roll the FTC-mandated alterations in to iOS's next point release, which many Apple watchers expect to drop "any day now."

Apple agreed to both the App Store adjustments and a refund program in the amount of $32.5 million in exchange for the dismissal of an FTC-backed lawsuit. The company did not appear to be happy with the idea of a settlement, with CEO Tim Cook saying it "smacked of double jeopardy" since Apple had already agreed to refunds for affected consumers and altered the App Store's behavior, but Cook chose to accept the settlement to avoid a "long and distracting legal fight" with the regulator.

Regarding the 13-year-old codebase, sometimes I think Apple should consider putting a team off to the side to rewrite iTunes from the ground up. Granted, space and bandwidth are trivial nowadays, but it amazes me that iTunes is currently consuming almost half as much space on my hard drive as Microsoft Office, which does a heck of a lot more. Also, having to download more than 100mb every time there's a sub-point upgrade can't be the most efficient way of doing things. And the program starts up slow and is noticeably sluggish when I move around within it. (Yes, my computer is not new, but iTunes runs less snappily than other programs, and it's not like it's inverting large matrices or something.)